Transmission devices for motor vehicles that have a continuously changing ratio are highly useful, both to provide a more comfortable ride, and to optimize engine efficiency for a given rotation speed. Several different types of transmission devices are known that comprise stepless speed change gears, but these transmission devices are cumbersome and cannot be incorporated into certain types of vehicles, such as for example, bicycles, motorcycles or other two-wheeled vehicles.
Therefore, there is a need for a new transmission device that has a continuously changing ratio, and that can be incorporated into smaller vehicles, such as motorcycles and bicycles.